Refrigeration systems



Dec. 9, 1958 J. L. AMMONS REFRIGERATION SYSTEMS 2 Sheets-Sheet 1 FiledApril 28 1955 H15 AGENT INVENTOR. Jose b]: L. Amm OHS Dec. 9, 1958 J. L.AMMONS REFRIGERATION SYSTEMS Filed April 28, 1955 Fig.5

LIQUID OUTLET GAS INLET WA TER OUTLE T 2 Sheets-Sheet 2 TIME WITCH 45REDWOOD DIVIDERS INVENTOR.

Joseph L. Ammpns WENT REFRIGERATTGN SYE'iTEMS .loseph lL. Ammons,Amariilo, Ten. Application April 28, N55, Serial No. 504,567 Qlairns.(Cl. 62-157) This invention relates to improvements in refrigerationsystems, and more particularly to a refrigeration system which uses aWater-cooled condenser with a scale eliminator, and also to a systemwhich utilizes hot gases in defrosting the condenser coils without thedanger of freezing these coils, with the incident hazard of burstingsame. The refrigeration system also has an ohm meter therein, which isof high sensitivity, to make possible the determining of the moisturecontent of the refrigerant.

Various refrigerant systems have been proposed heretofore, but these,for the most part, use a relatively large volume of water, either byrecirculation or wasting, to cool the hot refrigerant gases within thecondenser coils, however, in the present system the condenser is soconstructed as to give a maximum area of heat radiation surface of thecondenser coils, to enable a minimum amount of water to be used in thecooling of the condenser coils.

An object of this invention is to provide a refrigeration system with acooling tank surrounding the condenser coils, which will provide thefullest use of the Water, thereby using less water than is the generalpractice in other systems.

Another object of this invention is to provide a refrigeration systemwhich will prevent the collection of lime or other insoluble scale onthe coils of the condenser.

Still another object of this invention ispto provide a refrigerationsystem in which the refrigerant gas is reversibly deployed so as to usethe hot compressed gas to defrost the refrigeration coils, as desired.

A further object of this invention is to provide for the utilization ofa water cooled condenser with a reversible cycle for the refrigerantgas, so that the water cooled condenser will be free of the danger ofbursting during the defrosting cycle, and enabling the latent heat to bestored in the form of ice or chilled water, for future use forcondensation, when the refrigeration system is moved back to the normalcycle of operation.

A still further object of this invention is to provide an arrangementwhereby the refrigerant gas can be reversed, which will utilize arelatively large body of water as a source of latent heat to enable thedefrosting of the systen despite adverse conditions, such as low ambienttemperatures and the like.

Yet another object of the invention is to provide a refrigeration systemwhich provides an accurate and visible means for determining themoisture and acid content of the refrigerant.

Vtith these objects in mind, and others which will manifest themselvesas the description proceeds, reference is to be had to the accompanyingdrawings in which like reference characters designate like parts in theseveral views thereof, in which:

Fig. l is a diagrammatic, perspective view of the refrigeration system,with parts broken away and shown in section to illustrate the details ofconstruction;

Fig. 2 is an enlarged vertical, sectional View through a check valvewithin the system;

Fig. 3 is a vertical sectional view through a sight glass nited StatesPatent 9 and moisture indicator device, and showing an electrodetherein;

Fig. 4 is an enlarged sectional view taken at right angles thereto, onthe line 4-4 of Pig. 3, looking in the direction indicated by thearrows;

Fig. 5 is an enlarged, detailed, perspective view of the condensercoils, with a portion of the condenser coil tank broken away and shownin section, and showing scale eliminator electrodes attached thereto;

With more detailed reference to the drawing, the numeral 1 designatesgenerally a refrigerant compressor having a drive pulley 2, which is ofthe character to utilize (l-belts 3 for driving the compressor 1 by amotor 4. The compressor 1 and motor 4 are mounted on a base 5, inwhichbase a refrigerant receiver tank 6 is preferably housed. Arefrigerant gas discharge line 7 leads from the compressor 1 to afour-way valve 8. The four-Way valve 8 has a line 9 leading therefromwhich, under normal operation, is the refrigerant gas discharge line.The line 9 leads to a header 10 within a condenser tank ill. The headerin, as shown diagrammatically in Fig. 1, has three coils of condenserpipe 12 leading therefrom in a return bend fashion, with thelongitudinal reaches of the pipe being on a slight down grade, so astoconvey the condensed refrigerant gas into a lower header 13. Thecondenser coils 12 and the headers 10 and 13 are supported onnon-metallic insulating supports 14, as will best be seen in Fig. 5, soas to support the condenser coils and headers in spaced relation withrespect to tank 11, as will be more fully explained hereinafter.

A condensed liquid return line 15" leads from header 13 and dischargesinto receiver tank 6. The condensed refrigerant liquid flows fromreceiver tank 6 through pipe 16, which leads through a dryer unit 17,thence through a sight glass and electrode unit 13, to which electrodeand to which pipe is attached an ohm meter w. The refrigerant continuesto flow through pipe 16 to a branch pipe 20, in which a thermo-actuatedexpansion valve 21 is positioned. The branch conduit leads intoevaporator coil unit 22. The line 16a has a check valve 23 thereinwithin the by-pass between the evaporator coil 22 and the normal suctionside of expansion valve 21. The normal suction line 24 returns to oneside of the four-way valve 8, and with the valve 8 positioned, as shownin full lines in Fig. 1, the line 24 is in communication with a line 25leading to the suction side of compressor 1.

A thermo element 26 is in heat transfer relation to pipe 24 and isconnected thereto by the usual capillary tubing 27 which leads toexpansion valve 21, so as to actuate the expansion valve 21, inaccordance with the temperature requirements. A pipe 23 is connected, tothe normal refrigerant discharge line 9 at one end, and to a Watercontrol valve at its opposite end, which water control valve is within awater supply line 3ft which leads to the bottom of the condenser coiltank ll at one end thereof. A water outlet pipe 31 is fitted Withincondenser tank 11 near the top in the opposite end thereof, so as todefine a water level above the condenser coils l2 and headers it) and13.

The valve 8 is normally of the four-way manually actuated type, andwhich valve has a lever 32 thereon, which may be moved from the positionas indicated in full outline in Fig. l, to the dotted outline positionin the same figure. However, it is to be understood that this valve maybe time-clock controlled to move from one position to another for apredetermined length of time, and then move back to the originalposition.

The ohm meter 19 has wires 33 and 34 leading therefrom which Wiresconnect respectively to electrode 35 and clamp 36, the clamp 36 beingsecured about the pipe 16, through which pipe 16 the refrigerant flows.The electrode 35 is insulated from the body of the electrode unit 18 byinsulation 37, so that the probe 38, of

the electrode, will be immersed within the refrigerant gas liquor, whichliquors are usually of the trichloromonofluorornethane,dichloromonofluoromethane group or other refrigerants of the generalcharacter of these materials. The probe 38 is screw threaded and upontightening of the nuts, the insulation 37, which is of rubber-likematerial, is expanded so as to form a fluid tight seal with the body ofthe electrode unit 18. The probe 38 may be adjustably positioned withinthe chamber 38a so as to enable the correct reading to be obtained fromohm meter 10.

One side of the body 18 is open for the insertion of a sight glass 39. Asealing gasket 40 is positioned intermediate the glass 39 and the body18, and a screw threaded ring 41 threadably engages the body of theelectrode unit 18, so as to cause the sight glass 39 to bindingly engagegasket 40 to form a seal therebetween. While any ohm meter of highsensitivity may be used, it has been found that a vacuum type ohm metergives excellent results in determining the difference in resistancebetween a refrigerant liquid containing water, acids, or the like, and arefrigerant liquid without adulterants therein.

The line 16 has a check valve 23 therein, which is in by-pass relationto thermo actuated expansion valve 21 and is so arranged as to preventflow of refrigerant liquid from storage tank 6 through the check valve23 into the evaporator coils 22, but will permit the flow of hotrefrigerant gas from the evaporator coils 22 through spring pressedvalve member 42 and through a restricted orifice 43 into line 16, whenth handle 32 of the valve 8 is moved into the position indicated indashed outline, which will direct the gas outward from pipe 7 throughfour-way valve 8 into pipe 24.

The tank 11 surrounds coils 12, which coils and the pipe connectedthereto are spaced from the sides, ends and bottom of the tank by meansof insulating members, such as wooden support members 14, so that nopart of the pipe or the metal portion of the headers or coils is incontact relation with the tank. The tank is then filled with water,which water usually contains impurities which will normally form scaleon and cause corrosion of the condenser coils. Such water 'will attackthe metal and cause deterioration thereof, unless steps are taken toprevent such occurrence.

The coils 12 and headers and 13 are preferably made of an electrolyticmetal, such as copper, and the tank 11 is usually made of a negativemetal, such as galvanized iron, or the like. Electric connector wire 44connects to the pipe 9, which pipe leads to the coils 12, the connectorwire 45 connects to the tank 11. The opposite ends of the wires 44 and45 preferably connect with a time switch 46. The time switch 46 may beof a character which will close a circuit through these wiresperiodically, or which may be manually controlled, if desired.

The circulation of chemically pure water, for cooling the condensercoils and pipes, would be expensive, and furthermore is usually not sosatisfactory, as water containing some mineral solids is inclined toinhibit corrosion, but which impurities in the water forms a scale onthe condenser pipes which insulates same and retards the cooling actionof the water on the condenser coils. Therefore, it is desirable toremove the mineral solid deposit which collects on the condenser coilstherefrom by electrolytic action. The lime and mineral deposits thataccumulate on the condenser coils are transferred, by electrolyticaction, to the walls of the tank 11, where the lime deposit may bereadily removed at periodic intervals, thus maintainingthe coils at peakefficiency at all times.

However, if a continuous electric current, generated by electrolyticaction of the dissimilar metals of the tank and coils, is allowed, metalwill be removed from the coils and be deposited on the wall of thetank,;1.lntil the r 4 copper would be disintegrated. Therefore, the timeswitch 46 is set to open the circuit between wires 44 and 45 at periodicintervals, for the correct amount of time to remove the solids from thecoils and to close the circuit at the proper time to prevent injury tothe condenser coils, by by-passing the electrolytic current generated inthe tank directly from the coils to the tank.

As shown in Fig. 5, a thermo-actuated valve 29a, having capillary tubing29b leading into a thermo-bulb, is placed in contact relation withrefrigerant line 9 at a point near the condenser coils 12, or within theWater within the condenser coil tank 11, so as to be responsive to thetemperature of the fluid within the condenser system, that is, eitherthe fluid within the refrigerant line 9, or the cooling fluid within thecondenser coil tank 11.

In this manner, the valve 29a will be actuated to let water intocondenser coil tank 11 through water inlet pipe 30, when the water orrefrigerant gas rises above a predetermined setting of temperatureduring the refrigeration cycle of the system, however, upon reversal ofthe flow of refrigerant through the condenser, the chilling of the waterwill result in the closing of the valve 29a, which valve will remainclosed until the normal refrigerant cycle is restored and thetemperature of the water or of the refrigerant gas reaches apredetermined temperature, usually about degrees to degrees.

By having a refrigerant system wherein a relatively large body of wateris used for supplying sensible and latent heat, the use of this heat ismade possible both during the refrigerant cycle and the defrosting cycleto an advantage in each case, that is, the normal inlet watertemperature will usually be about 60 degrees, so in raising thetemperature from 60 degrees to the operating temperature of about 125degrees, sixty five degrees of sensible heat is given up from the waterin cooling the hot refrigerant gas, and since, the gas enters atsubstantially 125 degrees, this enables the maintaining of a lower andconstant head pressure, and since the temperature surrounding therefrigerant coil tank, is lower than that of the incoming refrigerant,and the outgoing cooling water, considerable heat is picked up from thesurrounding atmosphere, both by radiation and evaporation.

However, on the defrosting cycle, the chilling of the water in thecondenser coil tank and the frosting upand freezing of the water withinthe tank to a certain extent, enables the transfer of heat from theevaporator coil to the water within the condenser coil tank, whereby,upon initiation of the refrigerant cycle, the head pressure is loweredand since the changing of one pound of water at32 degrees temperature toone pound of ice at thirtytwo degrees temperature requires 144 B. t. u.,the latent heat of fusion stored within the ice, together with thesensible heat, enables the system to start refrigeration quickly withoutloss of efliciency, after defrosting.

Operation Normal refrigeration cycle.The compressor, which is driven bymotor 2, compresses the refrigerant gas which flows into line 7 throughvalve 8 into line 9, thence into header 10 and through condenser coils12, with the refrigerant gas condensing into a refrigerant liquor by thecooling action afforded by the water passing inward through pipe 30,pressure control valve 29 and into the bottom of tank 11. The cool waterpassing into the bottom of the tank, passes first in heat exchangerelation with the lower ends of the coils 12, and as the water is forcedinto the tank by pressure, it rises by both pressure and thermo action,and the outgoing hot water is in heat exchange relation with theincoming hot gas from header 10. When the water has performed its mostefficient cooling action, it passes outward through pipe 31, to bewasted, as the cooling of the water to a low temperature for reuse wouldgenerally be more expensive than the wasting of the heated water. As thehot gas is condensed into liquor, by heat exchange relation with thecold waenesgass ter, the liquor accumulates in header 13 and is carriedthrough line 15 into receiver tank 6.

The refrigerant liquor flows through line 16, dryer 17, electrode unit18 to and through thermo actuated expansion valve 21, and withsuctionbeing exerted on evaporator coil 22, by the suction line 24, connectedthrough four-way valve 8 to suction line 25 which connects with thesuction side of compressor 1, the liquid is vaporized and expands in theexaporator 22, whereupon it picks up heat and changes into a gas. Thisrefrigerant gas is drawn through normal suction line 24, valve 28,through suction line 25 into compressor 1, whereupon, the gas is againcompressed and is directed out through discharge pipe 7 to complete thecycle of operation.

As the cycle of circulation of the refrigerant medium within the systemcontinues, the heat given up by the chilling of the evaporator coils isdissipated by the condensor coils into the water within the tank 11. Asthe pressure in line 9 rises to a predetermined pressure, it will causethe pressure actuated water control valve 29 to open, due to theconnection of a pipe 28 between the pressure valve 29 and the line 9.The valve 29 is preferably of the graduated flow type, so that, as thepressure increases, the valve will open to such degree as to allow morewater to pass through conduit 30, through tank 11, and out throughover-flow pipe 31 so as to maintain the coils 12 at a given temperature.As the water cools the coils 12, the pressure therein is reduced and thevalve will close proportionately, until the water may be maintained inthe tank at a temperature at which the system is set to operate. Thevalve 29 will remain closed until such time as the water warms to atemperature which will necessitate the introduction of additional coolwater. By the introduction of cool water at the bottom of the tank atone end thereof, and withdrawing it from the top at the opposite end ofthe tank, a natural flow, by both thermo-circulation and by pressure,will move the heated water out at the point where the incoming hot gasesenter the coils. Therefore, greater efficiency of cooling is had, withthe minimum of heat loss in the heat exchange.

The method just described requires less water than is used by othersystems, as the present system allows no water to overflow until it hasreached the required temperature.

In actual practice, it is not necessary to use a cooling tower or otherrecirculation method, since this system uses less water in the coolingof the condenser coils than is lost through evaporation and bleeding offof warm water in a cooling tower. This not only cuts down the originalcost of the equipment, it reduces operational costs, and also conserveswater, which is particularly desirable in areas where water is notplentiful.

As a comparison of refrigeration capacity of the present device, acondenser tank of a three ton capacity refrigerating unit, the tank ofwhich is preferably ten inches wide, thirty inches long and 24 incheshigh and has a capacity of 20 to 25 gallons of water, after the coil isin place, which condenser coil 12 is approximately 150 of /s inchtubing.It is preferable to have multiple tubes 12 lead from a header, asindicated at and shown in Fig. 5, and shows seven coils leadingtherefrom to a header 13 so as to minimize back pressure. Due to thelength of travel of the refrigerant gas within the coils, and counter tothe flow of the water, the refrigerant passing into the header 13 issubstantially the same temperature as the cooling water being admittedinto tank 11 through pipe 31. In condensing the refrigerant, the headpressure is determined by the lowest temperature to which therefrigerant drops before it leaves the condenser. In the presentinstance the head pressure will correspond substantially to thetemperature of the entering water, because sufficient condensing surfaceand enough water are provided to absorb all the heat from therefrigerant before it reaches the header 13. A further advantage of theuse of a large volume of water, as used in the present device, is thefact that considerable cooling is had by radiation .6 from the tankandevaporation of the water into the surrounding air.

Conventional systems of three ton capacity usually utilize about 50 oftubing, holding in most instances, not more than one-half gallon ofwater. The water consumption of a commercial refrigeration system, istheoretically based on one gallon of water per ton of refrigeration perminute. In actual practice, the consumption more nearly approximates oneand one-half gallons per ton per minute, with the temperature of thewater rising to a maximum of degrees, whereas, in the present instance,the water is permitted to attain a temperature of to F., the Wateroverflows through pipe 31, which overflow is controlled by the incomingwater control valve 29. The evaporation from the surface of the waterand the overflow usually does not exceed one pint per ton per minute. Bybeing able to carry the heat so much higher, a much greater loss of heatthrough evaporation is possible, as 1 pound of water will absorb 750 B.t. u. in changing into steam. This condition is accelerated by the factthat the water is much warmer than the surrounding atmosphere.

Refrigerant systems are usually designed for intermittent operation andthe present system takes advantage of this fact by using hold over heatfrom the off cycle, that is, while the unit is oif, the water cools tonormal temperature and considerable heat is absorbed in bringing thetemperature of the water back to 125 to 135 F, the normal operatingtemperature.

Coilcction of lime and scale deposiZ.-When using cooling water, withinthe system, which has impurities therein, such as lime and varioussalts, the heat within the condenser coils 12 will normally causeincrustation of the pipes with a scale, which is the deposit of theimpurities within the water. This scale, as the coating thereof on thecondenser pipes becomes thicker, increases the insulation effect betweenthe cooling Water within the condenser tank Elli and the condenser coils12, which results in loss of efficiency within the system, and at thesame time, the chemical reaction of the lime, salts, or other inorganicmatter, which forms the scale, will attack the surface of the metal andcause deterioration thereof, and eventually failure.

With the condenser coil pipes 12 spaced from the walls and bottom of thetank 11 by insulating spacer members 14, the heat differential betweenthe top and the bottom of the water within the tank 11, will set up athermocouple, when a wire 44 is connected to the coils and a wire 45 isconnected to the tank, which wires are disconnected from the switch 46,which will result in a small but measurable amount of current flowingfrom the top of the coils to the tank and from the base of the tank backto the coils 12. The coils thus become an anode and the tank a cathode,which receives the electrolytic ions carrying the impurities anddepositing them on the walls and bottom of the tank, whereupon, atperiodic intervals, a time or manually actuated switch 46 is closed,which short circuits the current and consequently the flow ofelectrolytic ions from the anode to the cathode, which prevents theremoval of metal from the anode by the electrolytic action, but theswitch may be allowed to remain closed a sufiicient length of time topermit a slight accumula tion of scale of the coils 12, whereupon theprocess is repeated.

After a long interval of time, the water may be removed from the tank,and the accumulation of scale and electrolytic deposits, which form onthe walls of the tank as a fine powder, may be removed by mechanicalmeans, .zch as a wire brush, or the like. The removal of the scaledeposit from the coils, not only prolongs the life of the condensercoils 12 almost indefinitely, but it keeps them free of suchencrustation which acts as insulation and impedes the efliciency of thesystem.

Defrosting by means of hot gran-When it is desired to defrost therefrigeration unit, the valve lever 32 is turned "ant gas, that is, thehot refrigerant gas is discharged into line '7, through valve 8 intoline 24, whereupon this gas flows through evaporator coil 22 where it iscondensed,

'thereby liberating heat which melts the frost or ice which has formedon coils 22 and on radiation fins 22a. The

condensed liquid refrigerant will then flow through bypass loop 16a,through check valve 23, and orifice i3, thereby by-passing the expansionvalve 21', thence the liquified refrigerant is expanded by passingthrough orifice 43, thence the refrigerant gas flows through line 16into receiver tank 6, and the liquid refrigerant is drawn through line15, by the suction on coils 12. Whereupon, the liquid refrigerant entersheader 13 and as it passes upward through coils 12, heat is picked upfrom the Water within the tank 11 vaporizing the refrigerant into gas,which gas passes out through pipe 9, through valve 3, into pipe 25 tothe suction side of the compressor 1. In so doing the heat generated bythe hot gas defrosts evaporator coils 22.

The water in tank 11 is chilled by the expansion of refrigerant into agas during the reversing of the cycle of defrosting, thereby actuallycausing a heat transfer, which, upon reversal of the cycle, that is, theswitching of valve handle 32 from the dotted line position to that shownin full lines in Fig. l, the normal refrigeration cycle will berestored, so as to direct refrigeration gas outward from compressor 1through valve 8, through pipe 9 into header 1i and condenser coils 12.in the manner set out above, and the normal refrigeration cycle isrepeated.

For the reasons as explained above, no additional water is fed into tank11 until the ice is melted from the coils and the temperature of thewater has been raised until normal condensing temperature is reached orexceeded. Furthermore, this arrangement of the reverse defrosting cycle,enables sensible heat to be drawn from the water and used to heat thecoils to be defrosted. As the temperature of the water is lowered, belowfreezing, a tremendous amount of latent heat of fusion is liberated fromthe water, and since the volume of water in the tank is large, ascompared to the area of the coils, a large amount of heat may be used indefrosting without materially icing up the water within the condensertank 11.

Moisture indicat0r.--One of the most diflicult problems connected withrefrigeration, is the presence of moisture within the refrigerant.Moisture within the refrigerant system combines with the refrigerantgases and oil to form corrosive substances and/ or acids which attackthe internal parts of the refrigeration system, thereby materiallyshortening the life of the materials used, and the efiicient operationof the system.

Should the moisture contained within the refrigerant be of suflicientvolume, it will freeze out of the refrigerant into the expansion valve21, thereby plugging this valve, and thus causing the cessation of therefrigeration.

Heretofore, no means has been provided for determining the amount ofmoisture in the refrigerant during the normal operation of the system.However, the moisture content of the refrigerant frequently becomesexcessive, and freezes in the valve, before precautionary measures canbe taken. The presence of excessive moisture in the refrigerant alsocauses corrosion of the internal parts of the system and may causeserious damage thereto.

In the present refrigeration system, an ultra-sensitive ohm meter 19,which is preferably of the vacuum tube type, is provided, which makes itpossible to measure the resistance of the refrigerant by the passage ofan electrical current from an electrode, through the refrigerant, to thewall of the pipe, which pipe wall acts as a second electrode. Thus bymeasuring the resistance of unadulterated refrigerant, and by measuringthe resistance of moisture contaminated refrigerant, an indicia on thescale of the ohm meter 19, can be provided, which,

by showing the amount of resistance, will indicate the amount ofmoisture present. The indicia on the ohm meter scale may have theextremes indicated by red and green, so that the pointer of the ohmmeter will immediately indicate whether or not dangerous proportions ofmoisture contaminate the refrigerant fluid within the system. If adangerous amount of moisture is found to be present, proper steps can betaken, such as replacing the dryer 17, or such other measures as arefound to be desirable to correct the condition. The vital point here isto be able to determine that the condition exists.

As the moisture content of the refrigerant increases, the electricalresistance becomes less, the higher the ratio of water, the less theresistance of refrigerant, in direct proportion. With this knowledge,the proportionv of water within the refrigerant can be determined, and adryer of the correct size, to remedy the situation, may be installed, soas to eliminate the harmful effects of too much moisture within therefrigerant. Instead of the indicia of the ohm meter being calibrated inohms of resistance, the indicia may be prepared to indicate wet,

damp, dry or the like, for the information of the nontechnical operator,in addition to having the red and green indicia on the dial.

While a preferred embodiment of the invention, including the accessoryelements, have been shown and described herein, it is to be understoodthat changes may be made in the minor details of construction, withoutdeparting from the spirit of the invention, or the scope of the appendedclaims.

-Having thus described the invention, what is claimed is: 1. In acondenser unit for a refrigeration system having a compressor therein, acondenser coil tank, a condenser coil in said tank, said condenser coilbeing connected to said compressor in fluid communication to admitrefrigerant gas from said compressor into said condenser coil in saidtank near the top and at a side thereof,

said condenser coil having a downwardly meandering path to a point nearthe bottom of said tank, a refrigerant outlet pipe connected to saidcondenser coil near the discharge end thereof, a receiver tank, saidrefrigerant pipe interconnecting said condenser coil with said receivertank of said refrigeration system, awater outlet pipe connected in fluidcommunication to said condenser tank near the top thereof adjacent saidinlet pipe for said refrigerant gas, a water inlet pipe connected influid communication with said condenser coil tank on the side thereofopposite said water outlet and near the bottom of said, tank, a valvewithin said water inlet pipe, a pipe connected with the pipe leadingfrom said compressor to said condenser coil and to a pressure responsiveelement of said water inlet valve so as to admit water into said tank indirect proportion to the pressure within said pipe leading from saidcompressor to said condenser coil, said condenser coil being in spacedrelation from and out of electrical metallic contact with said condensercoil'tank, and electrical conductor means connected to said coil and tosaid tank, and switch means within said electrical conductor forselectively interrupting the passage of electrical current through saidelectrical conductor.

2. The device asset forth in claim 1, wherein; electrical insulatingelements are positioned intermediate ,the coil of said condenser andsaid receiving tank, a conduit connected with said receiving tank, andwith the other side of said evaporator unit, an expansion valve with nsaidconduit intermediate said receiving tank and said evaporator unit,control means on said four-way valve for directing compressed gas fromsaid compressor unit to said condenser unit and for directing a suctionon one side of said evaporator unit, or directing discharged gas outwardfrom said compressor to said evaporator unit and drawing a suction onthe upper side of said condenser coil, and a lay-pass conduit abridgingsaid expansion valve, a check valve within said by-pass conduit topermit the flow of refrigerant through said evaporator counter to thenormal flow therethrough during the refrigeration cycle, said checkvalve being positively closeable in a direction counter to the flow ofthe refrigerant fluid through said expansion valve, which check valvebody has a constricted orifice therein so as to form an expansion valvefor said refrigerant in the direction opposite said first mentionedexpansion valve.

4. The device as set forth in claim 1, wherein; said switch means is atime switch means.

5. In a refrigeration system having a compressor unit, a condenser tank,a condenser unit within said condenser tank, an evaporator unit, anexpansion valve, and a refrigerant receiving tank, a conduit connectingsaid compressor unit and a header, which header is positioned at theupper side of said condenser tank, a plurality of conduits within saidcondenser tank and passing downwardly therein, said conduits beingconnected to a second header positioned at the lower side of said tank,an outlet pipe, one end of which is connected to said second header andthe other end of which outlet pipe is connected in fluid communicationto said receiver tank, a conduit leading from said receiver tank to saidevaporator unit, said expansion valve being positioned within said lastmentioned conduit intermediate said receiver tank and said evaporatorunit, which expansion valve permits the passage of a refrigerant fromsaid receiver tank to said evaporator unit, a conduit leading from saidevaporator unit to the suction side of said compressor unit, a by-passconduit leading from said evaporator unit to said receiver tank inabridging relation with respect to said expansion valve, a positiveclosing check valve positioned within said by-pass conduit, which checkvalve positively closes on flow of said refrigerant in one direction butpermits restricted reverse flow of said refrigerant with respect to thenormal flow thereof through said conduit leading from said receiver tankto said evaporator unit, said by-pass conduit having an orifice formedtherein intermediate said check valve and said receiving tank, whichorifice is of reduced cross-sectional area with respect to thecross-sectional area of said by-pass conduit, and valve means withinsaid conduits leading from said compressor to said condenser and to saidevaporator for reversing the normal flow of refrigerant through saidcondenser and said evaporator.

References Cited in the file of this patent UNITED STATES PATENTS2,364,016 Wussow Nov. 28, 1944- 2,451,385 Groat Oct. 12, 1948 2,453,584Newton Nov. 9, 1948 2,589,855 Pabst Mar. 18, 1952 2,642,478 Lasky June16, 1953 2,748,571 Henderson June 5, 1956

